The invention relates to an apparatus for continuous annular chromatography, in which a relative movement between a particle bed in the form of a cylindrical jacket and at least one feed point for liquid feed material and at least one collection point for each feed material fraction emerging from the particle bed is provided by rotating the particle bed.
In column chromatography, a vertical cylinder is filled with particulate material and loaded at the top with a mixture of components which is to be separated. Elution is then effected continuously from the top with a solvent, the components, owing to their different affinities to the particle material, being separated in proportion to the flow rate of the solvent (eluent) and leaving the column in succession.
A distinction is made between the use of a single solvent (isocratic procedure) and the use of a plurality of different solvents (step or gradient procedure). In the step procedure, the solvent is changed without a transition; in the gradient procedure, the proportion of individual solvents in a solvent mixture is changed as a function of time.
In this elution chromatography, the components are simply washed through the column; if, on the other hand, a so-called displacer is used in the eluent, i.e. a component which has a higher affinity to the particle material than all previously added components and therefore displaces said components, the term used is displacement chromatography, in which fractions concentrated in comparison with elution chromatography are obtained, but not all of the individual components is obtainable in pure form (mixtures are always obtained).
Annular chromatography, in which a relative movement between a particle bed in the form of a vertical cylindrical jacket and at least one feed point arranged at the top of said jacket and intended for liquid feed material is provided and the individual components pass through the particle material along spiral paths and emerge simultaneously along the lower circumference of the cylindrical jacket in different circumferential regions, was developed to permit continuous chromatography. It can be used, for example, as HPLC, elution or displacement chromatography and is operated, in particular, isocratically. Continuous annular chromatography is abbreviated internationally to CAC.
Both apparatuses in which the particle bed is stationary and those in which the particle bed rotates relative to feed point(s) and collection points are known for CAC. EP-A 371 648 of Union Oil of California may be mentioned as an example of a publication which describes in detail the apparatuses of the second type, which are to be further developed by the present invention, and gives an overview of a very wide range of chromatographic methods.
U.S. Pat. No. 3,077,103 proposes a closed CAC apparatus in which the annular cylindrical chromatography jacket is mounted between two round end pieces. Two concentric side walls which form a furrow into which the chromatography jacket is rotatably inserted each project from the surfaces of the two end pieces. O-rings for guiding the chromatography jacket are provided between the outer walls of the cylindrical jacket and the inner surfaces of the side walls. To prevent bonding of the cylindrical jacket base at the bottom of the furrow, the jacket base is guided a distance away from the bottom of the furrow.
The object of the invention is to propose a simple measure which enables CAC apparatuses to be made insensitive to contamination by the environment, in particular to permit sterile operation.
Accordingly, in the apparatus according to the invention for continuous annular chromatography, in which a relative movement between a particle bed in the form of a cylindrical jacket and at least one collection point for each feed material fraction emerging from the particle bed is provided by rotating the particle bed, the baseplate of the annular cylindrical chromatography jacket rests on the collecting ring for the fractions emerging from the feed material and slides while providing a seal.
The otherwise usual discharge nozzles for the fractions emerging from the CAC column are in the form of channels in the liquid exit zone of the particle bed jacketxe2x80x94in other words, liquid channels running at least essentially parallel to the axial direction of the particle bed in the direction of the collecting ring and arranged equal distances apart are provided in the liquid exit zone of the particle bed jacket below the particle bed.
Furthermore, it is advantageous that a liquid-permeable strip for retaining bed material, in particular a strip of porous plastic, is provided between particle bed and liquid channels.
A further design according to the invention is that a wedge space adjoins each of the liquid channels in the direction of the particle bed.